Current tennis racquet designs provide a frame through which strings are threaded and placed under controlled tension. Modern racquet design typically provides “cleats” and “grommets” at the periphery of the racquet frame through which strings are threaded. These cleats and grommets are integral to the design of the specific racquet and are set at the time of manufacture. These cleats and grommets are fixed at the time of manufacture and are specific to particular racquet designs. Current designs do not permit variable selection of string pairs wherein increased elastic deformation can occur.
Typical string patterns provide for strings placed in one of two orientations relative to the long axis of the racquet; those oriented parallel to the long axis are referred to as “main strings” and those oriented perpendicular to the long axis are referred to as “cross strings”. The elliptical geometry of the tennis racquet frame of necessity produces differing characteristics of deformability or relative elongation capacity as strings are positioned farther from the center of the racquet; i.e. those strings that are more distant from the center of the racquet deflect to a lesser degree than those pairs of strings placed close to the center of the racquet given equivalent string tension and force of impact.
Racquet makers have attempted to address force distribution across multiple string segments in various ways. By allowing for reduced friction as the string passes through the frame, tension can be distributed across multiple string segments; current manufacturers produce a variety of mechanisms designed to achieve less friction at the critical points where string loops cross through the frame. Current mechanisms include: large holes through the frame with smooth surfaces, specialized materials comprising the through frame grommets providing a lubricious surface and multi-grommet frame inserts of elastic material that provide a compressible insert where string loops go through the frame. Current techniques for addressing these issues are manufactured at the time of racquet production and as such are “fixed” systems not providing for customization of elastic properties of string pairs at or after stringing is performed. Furthermore these designs impart a specific mechanical profile to specific designs. These systems do not permit the individual player an opportunity to tune his racquet to specific play characteristics or needs. Furthermore, as these designs are formulated to perform optimally at specific string tensions they do not address differing physical characteristics arising when a player specifies string tensions that are different from those for which the racquet system was optimally designed.